Triple Shadow Transit Across Jupiter - Oct 11-12

During the night of October 11-12, there will be simultaneous transits across the apparent disk of Jupiter by the shadows of three of its Galilean satellites. This has not occurred since 2004. For those who are wondering, having four simultaneous shadows is impossible. The shadows of Io, Europa and Callisto will all be in transit from 23:30 CDT to 00:46 CDT (UT-5).

I’ve created preview graphics of the triple shadow event as seen from above Jupiter’s north pole and as seen from Earth. They can be viewed at: www.CurtRenz.com/jupiter

Now that Jupiter is beginning to reenter our evening sky, I’ve resumed publication of my nightly event timetable and graphical array of Jupiter’s four Galilean satellites and their shadows. They can be accessed at the same webpage.

Photos and descriptions of the triple shadow transit would be welcome additions to this thread.

I'm curious about the impossibility of all four Galilean moons' shadows being visible. Sounds like a math problem...

Due to an orbital resonance a close grouping of all three of the inner Galilean satellites can never be viewed from Jupiter. It's one of the few true solar system resonances and is not merely an approximation. Callisto is not part of the resonance, so its shadow always participates in a triple shadow event.

You're Welcome, Pete. Another part of the reason that triple shadow transits are rather rare is that Callisto must always be involved. It goes through alternating periods of about three years each in which it either can or cannot cast a shadow on Jupiter. We recently entered on of those periods in which Callisto shadow transits are possible. In the cases of the three inner Galilean satellites, they always cast their shadows on Jupiter when they pass between Jupiter and the Sun during each synodic revolution around Jupiter.

Thanks for the clarification Curt. This is all new to me as I was totally out of the loop on orbital resonances. I can understand how Callisto would have times when no shadow could cast on the planet - when I think if just how very far out its orbit goes - its surprising to me that it can actually form a distinct shadow spot.

OK, Curt, I am always confused by this. I am in Arizona, so we are always on MST. On the evening of Oct 11-12 will the diagram you provided (thank you), will that be the same for Arizona at midnight my time?

OK, Curt, I am always confused by this. I am in Arizona, so we are always on MST. On the evening of Oct 11-12 will the diagram you provided (thank you), will that be the same for Arizona at midnight my time?

Thanks;
Steve Coe

Steve, the diagrams are for 00:00 CDT (beginning of Oct 12) which is 22:00 MST/PDT on Oct 11 or 05:00 UT on Oct 12.

Jupiter will be about 5 AU from us, so the viewing perspective will be nearly the same for all observers on Earth. Events will occur in virtually the same real time for all observers. Of course adjustments must be made for time zone considerations, as in my examples above.

During the afternoon and evening of October 11 you will find precise timing predictions on my Jupiter webpage: www.CurtRenz.com/jupiter

Elevation for me at mid-event is 11 degrees in Toronto... It will be a miracle if the seeing will allow anything to be seen at all.... It will be worse for folks much to the west of me because J. will be nearer the horizon.... Impossible to view in the west half of the continent......

Elevation for me at mid-event is 11 degrees in Toronto... It will be a miracle if the seeing will allow anything to be seen at all.... It will be worse for folks much to the west of me because J. will be nearer the horizon.... Impossible to view in the west half of the continent......

Dave

Well then, Dave, I hope you appreciate the challenge.

Indeed, this becomes tougher the further west one is located in North America. Those on the west coast may be unable to see any of the shadow transits, but they should be able to observe some of the transits of the actual Galilean satellites.

Here are my predictions for the transits including partial phases in Universal Time during 2013 OCT 12.

After posting I messed around with Sky Map Pro for a few minutes and found it will be up around 8 degrees of a flat horizon...that is not going to work well.

Phooey;Steve Coe

Are you sure? I live in New Mexico, and using Stellarium, I computed that Callisto's shadow will begin crossing Jupiter around 10:24pm, Mountain Time. Jupiter will then be about 20 degrees above the eastern horizon, about even with Pollux. Not sure which Time Zone that Arizona is in, but if you have a clear horizon, you should be able to see all three shadows, if you stay up late enough. (If I'm wrong, please correct me :-)

The triple event only lasts from 0432 to 0537 UTC so 0500 is a good mid-point estimate.

Pete, by my calculations those times are essentially for when the centers of the shadows will be on the limb and terminator of Jupiter's apparent disk. The times I gave in my earlier post include the partial phases when only an edge of a shadow touches the lit disk. On October 11 my Jupiter webpage will include a complete timetable of both the partial and total phases. My calculations are based on the high accuracy theory of the Galilean satellites by J.H. Lieske as reproduced by Jean Meeus in "Astronomical Algorithms". I invite observers to verify the accuracy.

My timetable for tonight's triple shadow transit across Jupiter and the later transits of the Galilean satellites is now available on my Jupiter webpage: www.CurtRenz.com/jupiter . It includes start and finish times for both the partial and total phases of the events. Timing verifications from observers would be appreciated.

Well for those of us who got clouded over, how is it looking for January 24, 2015? I tried plugging it into SkySafari but the transit is not updated in the software. What time is it scheduled to start? & if we miss that one, what day and time will we next have an opportunity to see it from the US Northeast in 2034?